There is known a method of inserting loops of continuous weft thread, including feeding the weft thread from a supply bobbin into an inserter needle or rapier and inserting the weft thread into the shed by reciprocating the needle or rapier,and securing the loops thus inserted at the front and rear selvages of the cloth being woven, in the direction of the motion of the needle or rapier (see, for example, an article by Eng. Kirhenberger in "Chemical Fibres for Textile Industry" Magazine published in the Federal Republic of Germany, August 1984, pp. 498-500, FIGS. 1 and 4).
According to this method, the weft thread is inserted into the shed by a needle through the eye of which the weft is threaded, the weft thread sliding through the eye of the needle and forming a loop owing to one end of the thread being secured in the selvage and the other end of the thread being pulled off the supply bobbin.
The existence of the friction engagement of the thread with the eye of the needle where the thread changes its direction through about 180.degree. results in the tension of the thread in the alternating runs of the loop (according to Eiler's law) varying at a ratio as high as 2.5:1. This difference in the thread tension can be substantially greater when the thread has such defects as swells, bulges, knots and the like. This leads to an increased weft breakage rate and adversely affects the productivity of the loom. For this reason the above described method would not be practically employed for inserting loops of weft thread across considerable widths of cloth; neither would it be employed for inserting weft thread of relatively low strength.